Friday, 10 April 2009

Whilst taking Chloe and Aidan's wedding group shots in Herne Bay's Memorial Park last Saturday, the weather was transformed from that of a gloomy winter's to a glorious summer's day in the space of 5 minutes as the sun burnt off all the cloud cover. My soft lighting was replaced by intense, high contrast lighting and there was no shade in sight.

What can you do in this situation?

Well, you should certainly try and avoid that old adage about 'keeping the sun behind you'. This will direct the sun into your subjects' faces, often causing them to squint, and can easily cast shadows under their brows (causing 'panda eyes') and noses - not very attractive. Even if you get away with this, the lighting can often look flat.

Try putting the light behind your subjects, as in the shot above. You may need to exposure compensate depending upon the tonal distribution of the shot. Expect to see the sky being burnt out though - don't worry about an unhealthy-looking histogram, we're only interested in detail in the subjects' faces.

Here's a close-up of Chloe and Aidan - no squinting, no shadows on their faces. The rim-lighting (and shadows in front of the group) also add depth to the shot.

Two more examples of shots taken under these conditions - strong, high contrast lighting with no shade.

One caveat - if the sun really is directly above you (most likely at midday in mid-summer in the UK) then you won't be able to avoid shadows on your subjects' faces. Open shade will have to be sought under these circumstances.

Side-lighting can also add depth to a shot. You just need to decide if the shadows created are too great a distraction for your purposes.

Many thanks for your comment. I should have addressed this issue in my initial post.

As you rightly point out, underexposing for ambient light and then lighting the subject with flash is a great way to add drama to a shot.

The factors to consider when doing this are:

1. The difference in exposure between the subject and the background.2. The subject area that needs to be lit.3. The number of shots that need to be taken in this situation.

In my example above, all of these factors were against me applying this technique.

With the sun at full tilt mid-afternoon there was at least a 5-stop difference between the sky and the faces of the guests and I had to take lots of large group shots.

Lighting wedding groups evenly under these conditions is beyond the three Canon 580EX II Speedlites I have in my bag!

To have a few shots without the sky being blown out (there were no clouds but the sky was a lovely blue away from the sun) I shot a few groups with sidelighting. A blue sky is a more manageable middle-grey tone.

Thanks for that detail David. So just to clairfy - you did not use flash in that shot? I'm not too clear on what the thinking is with point 1 in your reply.

David, I'm keen to know at what point you decide to turn off your flash outdoors. For example, in your full length portraits of the couple (over 100mm focal) would there be any point using flash on a bright day? I'm guessing the shutter speed would always be above the flash sync, so would even FEC+2 give enough power to make a difference?

David , was there a reason you went with F8 for this shot? With the crowd in a level line you could have gone wider right?

underexposing for ambient is difficult in daylight as the shutter speeds become so high, the Speedlight HAS to work in high Sync mode, reducing it's range a lot - I think about 7ft is your limit. David what do you think?

2. To address point 1 in my original reply let's look at some hard exposure figures (also check out my post on exposure values for some background info).

To expose correctly for faces in the group shot (the subject) required 1/125, f/8.0, ISO 100 (we'll ignore the exposure compensation tweak) - this equates to an exposure value of 13.

If I had wanted to expose correctly for the sky (the background) the exposure would have been in the region of 1/4000, f/8.0, ISO 100 - an EV of 18 and a 5-stop smaller exposure than that required for the group shot. If I'd wanted a bit of drama I would have needed to underexpose in addition. If I did so by a further 2 stops (ie 1/8000, f/11, ISO 100) the subject matter would now be 7-stops underexposed - and I'd have to make up this difference with my Speedlites!

This is a huge amount of light which is beyond the capabilities of Speedlites. Their output is further limited under these conditions since the X-sync speed on my camera is 1/250 so we'd have to set the Speedlites to high-speed sync (FP) mode which reduces power output to about 1/3. Also the smaller the aperture of your lens the harder the flash unit has to work - and we're at f/11!

3. Using flash outdoors is a judgement call based upon the factors I mentioned in the original post - primarily the exposure balancing required and the subject area that needs to be lit (both of these determine the amount of power output required).

4. I probably could have used flash with the couple shots to just add a 'kiss of light' - I was shooting at f/2.8. Speedlites have a Fresnel lens for focusing light (up to a focal length of 105mm on my 580EX IIs). Having said this, I would probably have taken the flash off-camera though and had someone holding a Speedlite just out of frame and directing the light for me.

5. Flash units are quickly overwhelmed outdoors!

On to Peter's comments:

6. f/8.0 - f/11 is generally the sharpest aperture of a lens. If I can, I try and shoot groups at this aperture as well as the crowd-pleasing wider apertures!

7. High-speed (FP) sync mode reduces output to about 1/3. Range will depend upon the aperture you're shooting at but it probably won't be far from the figure you suggest.

Very interesting David - thanks. I've never really bothered looking at things in terms of exposure value charts.

So if I want to maintain wide apertures in sunshine with no shade to use - my only option is to stick an ND filter on right? If I use a very strong ND to bring the shutter speed back out of the Speedlite high sync mode - I should regain much more power from my flash I imagine. Just thinking aloud - what do you think?

David, something else I've been meaning to ask is if you know the reason why you can adjust EV -/+ 3 in the camera, but only -/+ 2 in the shooting modes?

If you're at your lowest ISO setting and fastest shutter speed and still can't reach the aperture you require then an ND filter will certainly allow you to access a wider aperture.

You might be able to reach the X-sync speed with a wider aperture with an ND filter present, allowing you to access the fullest power your Speedlite offers, but the filter will block several stops worth of this power too.

The exposure level indicator in most SLRs only shows you a range of +/- 2 stops. Obviously in manual mode you can have any exposure you choose, provided you can do the mental calculation!

The 1D series of cameras offers +/- 3 stops of exposure compensation - I was hoping to see this incorporated in the 5D Mk II.